Necrotizing enterocolitis is a serious disease affecting the intestines of a newborn baby. It involves a severe inflammation that damages and kills tissues in the baby’s colon, resulting in complications, including death.

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Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in neonatal intensive care units (NICUs) in the United States. It is responsible for almost 8% of all NICU admissions.

This article explores NEC and its symptoms, causes, diagnosis, treatments, complications, preventions, outlook, and frequently asked questions.

NEC is a life threatening disease with a survival rate of around 44%.

It almost exclusively affects newborns and occurs in one in every 1,000 live births. While it can occur in full-term infants, nearly 70% occurs in preterm infants born before 36 weeks of gestation. It is also much more common among very low birth weight infants or those who weigh under 1,500 grams.

NEC happens when bacteria invade the walls of the intestines, causing infection and inflammation. As the disease progresses, the inflammation causes a lack of blood supply in the tissues, leading to tissue death, or necrosis, and holes, or perforations, in the intestines.

Experts describe NEC symptoms as:

  • nonspecific
  • subtle
  • highly variable

However, many parents report the following symptoms, which tend to appear in the first weeks of life and may develop suddenly or over days:

  • an inability to digest food
  • bloating or swelling of the stomach
  • reddish or bluish stomach discoloration
  • abdominal tenderness to palpation
  • blood in the stool or change in frequency or volume
  • diarrhea
  • decreased activity, or lethargy
  • vomiting greenish-yellow liquid
  • an inability to maintain a typical temperature
  • a temporary stop in breathing, or apnea

As the disease progresses, systemic signs can also appear:

  • respiratory failure
  • circulatory collapse, or a weak pulse or drop in blood pressure
  • decreased peripheral perfusion, which refers to a reduced blood flow to bodily areas further from the heart
  • unresponsiveness
  • cyanosis, when the hands, fingertips, or feet turn blue or gray because they are not getting enough oxygen-rich blood

Doctors do not know the exact cause of NEC, but it may occur if insufficient oxygen and blood reach the intestinal tissues. This hindered or blocked flow may damage the intestinal lining, making it more permeable and susceptible to bacterial invasion.

Gastrointestinal tract immaturity in preterm infants seems to have a factor in NEC. The alteration of the gut microbiome, which doctors call gut microbiota dysbiosis, may also contribute to intestinal inflammation and damage in infants with NEC.

Factors that put infants at risk of NEC include:

  • premature birth
  • a low birth weight
  • high osmotic strength formula feeding, due to fortification (extra nutrients in the milk)

It may also occur as outbreaks in NICUs. One 2020 study suggested a possible association between diazoxide exposure for persistent hypoglycemia, or low blood sugar, and NEC development.

An essential test to diagnose NEC is a series of abdominal X-rays. Other diagnostic procedures include ultrasound and blood detection in the stool.

The presence of the following in the X-ray could indicate NEC:

  • the air within the intestinal wall
  • dilated loops of bowel
  • portal venous air, where gas builds up in the portal vein

The treatment of NEC varies depending on the child’s age, symptoms, and general health, but it generally includes standard resuscitation according to a person’s vital signs.

The main treatments for NEC include:

  • discontinuing feeding, or enteral feeding
  • providing nutrition through a vein, or total parenteral feeding
  • gastric decompression
  • broad-spectrum antibiotics

It may also be necessary to insert an orogastric tube to remove air and fluid from the stomach and intestines. Doctors will insert this through the mouth.

Doctors may provide fluid resuscitation if the infant has low blood pressure or an endotracheal tube that goes in via the mouth and into the lungs.

The presence of air in the abdominal space, or pneumoperitoneum, indicates bowel perforation and urgently requires surgery.

Perforations in the intestine may lead to the contents of the intestine spilling into the abdomen, leading to complications such as:

  • sepsis
  • air within the wall of the intestine, or pneumatosis intestinalis
  • death

Prolonged total parenteral nutrition may lead to liver failure. Aside from prolonged hospitalization and treatments, other long-term complications include:

  • postoperative strictures, or tightening of the bowel
  • bowel adhesions, or scar tissue around the bowel
  • cholestasis, or liver disease
  • short bowel syndrome
  • issues with growth
  • neurodevelopmental delays

Ideally, doctors feed at-risk infants with breastmilk, but preterm formula is an appropriate substitute. Feedings should start small and gradually increase to standardized protocols. It is also ideal to avoid the following:

  • drugs, especially antibiotics, which may cause dysbiosis
  • hypertonic formula
  • contrast material
  • acid-suppressing drugs

According to 2022 research, breastfeeding and feeding with probiotics were protective factors for NEC in low birth weight infants. However, further studies need to determine the appropriate strains and optimal dosing.

Doctors may also give pregnant people at risk of preterm birth corticosteroids to prevent NEC.

The outlook for NEC depends on the severity of the condition in the child receiving treatment.

The mortality rate ranges from 10% to 50%, but infants with advanced NEC often experience intestinal perforation and have mortality rates approaching 100%.

Below are some frequently asked questions about NEC.

What causes NEC in newborns?

Doctors still do not fully know the cause of NEC, but they think the lack of oxygen supply and the immaturity of the intestinal tract makes it prone to ischemia — a lack of blood supply to a part of the body — and damage. A damaged intestinal wall makes it prone to bacterial invasion and inflammation.

How do I know if my baby has necrotizing enterocolitis?

Symptoms are nonspecific but often appear in the first weeks of life. Some of these include:

  • feeding intolerance
  • lethargy
  • temperature instability
  • bloating

Can doctors cure NEC?

Most infants with necrotizing enterocolitis fully recover without developing further problems. In some cases, they develop long-term complications such as intestinal scarring and neurodevelopmental delays.

What is the treatment for NEC?

The treatment of necrotizing enterocolitis depends on the severity of the condition and its symptoms. These include:

  • stopping feeding by mouth
  • fluid resuscitation
  • providing total parenteral nutrition
  • surgery

Necrotizing enterocolitis (NEC) is a disease of the intestine that mainly affects premature babies. Preterm infants are at a higher risk due to circulation issues and decreased intestine oxygen supply, making them prone to bacterial invasion.

Symptoms of NEC include feeding intolerance, lethargy, temperature instability, and bloating. Treatment depends on the severity of the condition and may involve stopping feeding, fluid resuscitation, and surgery.

The mortality rate of NEC is high, but infants may recover without complications if they receive timely treatment. A person should discuss possible preventive strategies with a pediatrician, such as breastfeeding at-risk babies.